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排序方式: 共有134条查询结果,搜索用时 15 毫秒
1.
A. D. Pogrebnyak O. V. Bondar B. Zhollybekov S. Konstantinov P. Konarski V. M. Beresnev A. I. Kupchishin 《Physics of the Solid State》2017,59(9):1798-1802
Multilayer nanostructured coatings consisting of alternating MoN and CrN layers were obtained by vacuum cathode evaporation under various conditions of deposition. The transition from micron sizes of bilayers to the nanometer scale in the coatings under investigation leads to an increase in hardness from 15 to 35.5 GPa (with a layer thickness of about 35 nm). At the same time, when the number of bilayers in the coating decreases, the average Vickers hardness increases from 1267 HV0.05 to 3307 HV0.05. An increase in the value of the potential supplied to the substrate from–20 to–150 V leads to the formation of growth textures in coating layers with the [100] axis, and to an increase in the intensity of reflections with increasing bilayer thickness. Elemental analysis carried out with the help of Rutherford backscattering, secondary ion mass spectrometry and energy dispersion spectra showed a good separation of the MoN and CrN layers near the surface of the coatings. 相似文献
2.
We consider the competitive facility location problem in which two competing sides (the Leader and the Follower) open in succession
their facilities, and each consumer chooses one of the open facilities basing on its own preferences. The problem amounts
to choosing the Leader’s facility locations so that to obtain maximal profit taking into account the subsequent facility location
by the Follower who also aims to obtain maximal profit. We state the problem as a two-level integer programming problem. A
method is proposed for calculating an upper bound for the maximal profit of the Leader. The corresponding algorithm amounts
to constructing the classical maximum facility location problem and finding an optimal solution to it. Simultaneously with
calculating an upper bound we construct an initial approximate solution to the competitive facility location problem. We propose
some local search algorithms for improving the initial approximate solutions. We include the results of some simulations with
the proposed algorithms, which enable us to estimate the precision of the resulting approximate solutions and give a comparative
estimate for the quality of the algorithms under consideration for constructing the approximate solutions to the problem. 相似文献
3.
针对纤维材料变温环境力学性能测试的需要,在华中科技大学研制的纤维材料试验机的基础上引入了温控装置,从而实现纤维材料在高低温环境下的力学性能测试。采用该装置对不同直径微米铜丝在不同温度、不同拉伸速率条件下的力学性能开展实验研究,测试结果表明弹性模量和抗拉强度随温度的降低而线性增加,屈服强度的变化不太明显。另外,低温环境下微米铜丝的力学性能表现出与其直径相关的尺度效应,而这一现象在常温下一直没有观测到。最后,还研究了拉伸速率对微米铜丝的力学性能影响,结果表明,在现有装置的许用范围之内,拉伸速率对其力学性能的影响不大。 相似文献
4.
CHEN Hong-jie LI Sheng LI Zhi-wei WU Zhi-shen ZHANG Ping-yu ZHANG Zhi-jun 《高等学校化学研究》2005,21(6):646-649
IntroductionMetal or alloy nanoparticles,because of their con-spicuous physicochemical properties,have been widelyapplied to various fields such as electronics,catalysis,magnetism,and corrosion-resistant materialsfields[1—4].It has been estimated that the particle sizeand the properties of nanoparticles depend strongly onthe specific method of fabrication and the applied ex-periment conditions,which makes the controlled syn-thesis of nanomaterials become an increasingly activeand important ar… 相似文献
5.
6.
电感耦合等离子体-发射光谱法(ICP-AES)快速测定饮用水中8种微量元素 总被引:4,自引:0,他引:4
用电感耦合等离子体-发射光谱法(ICP-AES)同时快速测定饮用水中微量的铜、铅、锌、铁、锰、镉、铬、砷,具有快速、简便、灵敏度高等优点,精密度为1.2%~8.2%(RSD,n=5).回收率为90%~110%. 相似文献
7.
M. N. Smirnova L. V. Goeva N. P. Simonenko E. N. Beresnev M. A. Kop’eva V. A. Ketsko 《Russian Journal of Inorganic Chemistry》2016,61(10):1301-1306
The gel formed in the synthesis of Mg(Fe0.8Ga0.2)2O4 powder from corresponding metal nitrates and glycine was studied by thermal and IR spectral analyses. Being a bidentate ligand, glycine was established to initiate the gel combustion reaction resulting in the oxide of the above composition. Based on the data on ΔH298° and Cp of the reagents and reaction products, the thermodynamic parameters of this process were calculated. 相似文献
8.
E. N. Beresnev M. N. Smirnova N. P. Simonenko S. V. Makaev M. A. Kop’eva O. B. Kuznetsova V. A. Ketsko 《Russian Journal of Inorganic Chemistry》2016,61(8):1026-1030
The thermal behavior of the gels that are formed in the synthesis of MgFe1.6Ga0.4О4 powders was studied by differential scanning calorimetry and thermogravimetry (DSC–TG). The combustion temperatures of the gels in flowing air and flowing argon were determined from experimental data and thermodynamic calculations. The calculations of combustion temperatures from the heat flow of reaction versus time are shown to be a reliable tool to determine the parameters of gel combustion. 相似文献
9.
A. D. Pogrebnjak A. A. Dem’yanenko V. M. Beresnev O. V. Sobol’ O. M. Ivasishin K. Oyoshi Y. Takeda H. Amekura A. I. Kupchishin 《Physics of the Solid State》2016,58(7):1453-1457
The recrystallization of the structure of an X-ray amorphous AlN–TiB2–TiSi2 coating containing short-range order regions with characteristic sizes of 0.8–1.0 nm has been performed using a negative gold ion (Au–) beam and high-temperature annealing. Direct measurements using methods of high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectral (EDXS) microanalysis have demonstrated that thermal annealing at a temperature of 1300°C in air results in the formation of nanoscale (10–15 nm) phases AlN, AlB2, Al3O3, and TiO2, whereas the ion implantation of negative ions Au– leads to a fragmentation (decrease in the size) of nanograins to 2–5 nm with the formation of spheroidal gold nanocrystallites a few nanometers in size, as well as to the formation of an amorphous oxide film in the depth (near-surface layer) of the coating due to ballistic ion mixing and collision cascades. 相似文献
10.
This paper deals with robustness of adaptive control of continuoussystems subject to known output delay, input saturation, unmodelledlinear dynamics, and bounded disturbances. A simple gradient-typealgorithm with a relative deadzone is used. The relative deadzoneis built with an estimated contribution of the unmodelled dynamicsto the system output. The basic tool used for stability androbustness analysis is Gronwall's lemma. 相似文献